Percussion-tool.



H. THIELE.

PERCUSSION TOOL. APPLICATloN FILED JULY 25,1911.

Patented Dec.

onen.'

HANS THIELE, F FIEDENAU', NEAR BERLN, GERMANY, ASSIGNOP. TO SIEMENS- sciincn'nnrvvnmts e.

GERMANY.

M. B, H., 0F BERLIN, GERMANY, A CORPORATION OF PERCUSSION-TOOL.

annesse.

Specification of Letters Patent.

Patented Deca 1, 1.915.

Applicationled July 25, 1911. Serial No. 640,518.

/'o all 1c/0m 'it may concern:

Be it known that l, Hans THIELE, a subject of the Germanv Emperor, and residing at Friedenau, near Berlin, Germany, have invented certain new and useful improvements in Percussion-Tools, of which the following is a specification.

lily invention relates to percussion tools 1n which the operative 'tool is not only driven axially but also rotated about its longitudinal axis.

he object of my invention is to improve and simplify the rotating devices in tools of this character,

My invention is particularly applicable to those percussion tools which comprise a rotating driving member, and in which .the percussion member formed as a cam acting on the operative tool is drawn backward by a rotating cam against the action ot a spring and is then released 'to iy forward, the pressure of the cams one on another producinga torque which the one cam must `resist if the percussion memberis to be drawn backward, as is intended, by the rotatory motion.

lborne illustrative embodiments of my in- '.on are represented by way of example in the accompanying drawing, wherein Figure l is a longitudinal section throu h one term of my improved percussion dm' l; '3. 2 is a detail view showing partsot the ne in elevation and parts in longitudinal 'im and Figs. 3 and et show two terms of Je tools or cutters adapted to be used drill', Fig. is a longitudinal section e in Fig. t5 showing a simplified of drill, Fig. 6 is a transverse section ,e line 6 4), Figf, showing how the brake may be applied to the bushing to rel. rotation of the tool, and Fig. 7 is a transverse section on the lineZ Z of Fig. 5.

Referring firstly to l*`igs. 1 and 2, a casing itains the socket or sleeve driven by ot its rod Y, by an electric motor. The of this socket is imparted by the to the cam /Z which drives the correng counter cam e, forming part of the on member e against the action of prmg f. After the one spiral cam has rotated a certain distance relatively to the other the cam constituting part of the percussion member is suddenly released by the other and is thrown forward onto the operative tool. or cutter. Tvll/*hen the one cam is rotated by the motor it exercises on the counter cam. a force which can be resolved into an axial and a tangential force. The latter was heretofore always taken up by suitable guides on the stationary parts of the tool; accordingto my invention I utilize it for directly rotating the operative tool, whereby the speed of the tool rotation is retarded over the speed of the rotating driving cam by means of a break action.

As the tool represented in Fig. l is to bev used both with and without the turning movement, for the sake of clear-ness l will first explain how the rotatory motion of the operative tool is prevented. To this end, in the illustrative embodiment the percussion member e squared in front is guided inI a bushing g having a suitable hole through it and simultaneously serving as abutment for the cam zZ. rlhe bushing g is itself prevented from rotating in the casing a. by teeth y, which engage with the teeth g., on the bushing z, which, on its part, is axially vdisplaceably but non-revolubly mounted in the head ol' the casing by means of the key z'. A spring m` presses the bushing against its seat in the head of the casing, as clearly shown in Fig. Now in order to use the tool without turning the operative tool, the latter is made as shown in Fig. 4: with a cylindrical projection /c able to pass freely through the square hole in the bushing g to within reach of the percussion member e. The collar Z then rests against the lower end of the bushing It. W hen the operative tool is driven it does not rotate because it contacts only with parts which are unable to rotate, and because the connection between the members g and it is never broken whether the bushing l1, is axially shifted more and more by pressure on .the tool in order to tension the spring f more or less. It', on the contrary, the operative tool shown in Fig. 4

Vis replaced by that shown in Fig. 3 having ifov ' Owing to the resistance,

spring f now acts .I be retarded at will.

. ber,

.ing g2 by the spring m the velocity of the driving motor and the percussive motion would .y entirely cease. however, which the operative tool or cutter experiences when it is pressed, owing to the frictiongon the workpiece, the rotatory motion .is retarded so greatly that the percussive motion remains to the desired extent.

Whereas Figs. 1 and show a percussion tool in which the essential device for. obtaining automatic turning` of the operative tool is connected with the known device lfor regulating the capacity by vmore or less severely compressing the spring f, Fig. 5 shows a somewhat simpler tool. Similar' reference letters designate like parts of the tool. In this embodiment the bushings g and t are united, as it were, to form one single bushing g2, and as its rotatory -motion isnot prevented ordinarily the operative tool is constantly rotated. The speed of rotation of the operativetool depends, of course, on the tangential force between the two cam-like members, and the resist.

ance of the friction which the bushing g2 experiences whenv rotating. The pressure of the spring m can now be proportioned so .that the frictional moment produced by it is somewhat less than the torque imparted at the beginning of the stroke by the percussion member to the bushing. Con sequently, a part of the rotatory motion. of the cam d is imparted to the percussion mem to the bushing g2 and also to the oper- The back pressure of the directly on the upper edge of the bushing g, through the medium of the cam d axially displaceable in the socket Atthe beginning of the stroke this back pressure is small, but increases as the stroke increases, and finally increases the friction pressure constantly exercised on the bushthat the bushing g2 and with it the operative tool w is held before the stroke 1s terminated and the blow ative tool w.

released. Thus the turning movement is suitably regulated.

Both in percussion tools according to Fig. 1 and in those according to Fig. 5 it may be desirable' to beA able readily to -adjust the speedv at which the operative tool turns. To this end, it is simplest to increase the friction between the bushing carrying the operative tool and the head of the casing, as is represented for instance in Figs. 5 and 6. 'As shown in these figuresv two lat-. eral brake shoes 1 are disposed adjacent to bushing., g2, which may be more or less tightenedagainst `the bushing by means of thumb screw q', and thus the friction produced thereby and the speed of rotation may Brake shoes r are disposed in' an enlarged portion of the lower drill casing a1, and pivotally held therein by pins s which may be inserted from the outside through the lower` end of the casing as shown indotted in Fig. 5.

Obviously thefdetails ofthe described device can be modified in various ways. Primarily, it is only essential that a torque produced when the percussion mass is drawn backward be utilized for turnin the operative tool, while by means of a ditional arrangements, such as are shown in the drawings, auxiliary operations,l such as cutting `in and cuttingl out the turning motion, regulating the capacity, and the like, can be obtained. v I claim z- A 1. In a percussion tool, the combination with a casing, a socket revoluble therein, a cam driven by the socket, and a springpressed percussion member having a squared portion and having a part formed as a counter cani in the socket 'co-acting. with the former'cam, of a bushing having a..

-. casing and containing the square portion of the percussion member,` and an operative tool having a squared end in the bushing, said bushing adapted to be rotated by the percussion member.

2. In a percussion tool, the combination, with a casing, a socket revoluble therein, a cam rotated by the socket, and a... springpressed percussion member having g, squared portion and having a part formed as a counter cam in the socket eo-acting with the former cam, of a spring-pressed bushing having a square hole mounted in the end of the casing and containing the l square portion of the percussion member, and an operative tool having a squared end in the bushing adapted to be rotated by the percussion member.

meV

3. In a percussion tool, the combination with a casing, a socket revoluble-therein, a cam rotated by the socket, and a spring- 'pressed percussion member having a part formed as a counter cam in the socket coacting with the former cam, of an operative tool, and means adapted to be rotated by the percussion member and to rotate the said tool, means connected with said former means for reducing the torque imparted by the percussion member to thetool,l and a controllable brake for aiding said reducing said bushing in frictional engagement with V the casing whereby the torque lmparted by the counter cam to the tool is-reduced.

5. In a percussion tool, the .combination with :i casing, a socket revoluble therein, a mim rotated by the socket, and a springpi'essed percussion member having a squared portion and having a part formed as a counter cam in the socket 3o-acting with the Jformer cani, an operating tool, a bushing adapted to 4be rotated by the percussion member and to rotate said tool, and a flange on said bushing in spring-pressed engagement, with the casing whereby the torque imparted by the counter cam to the tool is y HANS THIELE.

Witnesses HENRY HASPER, VVOLDEMAR HAUPT. 

